|Publication number||US3778748 A|
|Publication date||Dec 11, 1973|
|Filing date||May 5, 1972|
|Priority date||May 5, 1972|
|Also published as||CA977053A, CA977053A1|
|Publication number||US 3778748 A, US 3778748A, US-A-3778748, US3778748 A, US3778748A|
|Original Assignee||Allis Chalmers|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (4), Referenced by (9), Classifications (6)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent 1191 Holman 1 1 Dec. 11, 1973 STAB CONNECTOR 1,965,181 7/1934 Gerlach et al 339/64 M Inventor: Burdeue M. Holman, Brookfield 3,566,335 2/1971 Powell 339/64 M FOREIGN PATENTS OR APPLICATIONS  Assignee; Allis-Chalmers Corporation, 806,567 9/1936 France 339/196 A Milwaukee, Wis.
Primary Examiner-Joseph H. McGlynn  Ffled' May 1972 Attorney-Robert C. Jones et al. [211 App]. No.: 250,572
 ABSTRACT  US. Cl 339/64 M, 339/22 B, 339/196 M,
339/255 R A stab connector comprising an insulated body por- 51 Int. c1 H0lr 13/62 with a convenient quick insert which Carries a  Field of Search 339/22 64 195 P Of duhle P OfCOhIaCIS Biasihg means Within 7 the insert operate on the contacts to resist forces which tend to move the contacts away from each  References Cited other and as a result ensures positive electrical en- UNITED STATES PATENTS gagement of the contacts with the buses.
1,277,071 8/1918 Hastings et a1 339/255 R 8 Claims, 8 Drawing Figures STAB CONNECTOR BACKGROUND OF THE INVENTION Connectors of the stab type are known and are in present day use. The known stab type connectors either utilize a single bayonet type of stab connector or are provided with a pair of opposed contacts which are spaced on centers which are narrower than the conductor to be engaged. In this type of an arrangement the inherent resiliency of the metal of which the stab connectors are manufactured is relied on to establish good electrical contact between the contacts of the connector and the conductor. However, in this type of arrangement misalignment between the contacts of the stab connectors and the conductor to be engaged can result in one of the contacts of the stab connector having less than good electrical contact with the conductor. As a result, a high resistance between the loosely engaged contact and the conductor is experienced, as well as arcing and also erosion of the contact plating thus occurs, shortening the usable life of the connector as well as being a source of malfunction.
SUMMARY OF THE INVENTION The present invention provides a simplified, compact stab connector of a moulded contact holder and a moulded housing which are capable of being manually assembled without the use of tools. The holder is adapted to accommodate at least a pair of opposed spaced tubular contacts arranged to have limited lateral movement. A spring operates on the contacts to urge their outermost ends towards each other in a pincher action to insure positive electrical engagement of the contacts with a conductor.
An object of the invention is to provide a simplified electrical connector having contacts in which the area of engagement with a conductor remains constant even though there is some misalignment of the contacts relative to the conductor.
Still another object of the invention is to provide a connector wherein the pressure exerted by each contact on an engaged conductor is constant even though misalignment betweenthe connector contacts and the conductors exists.
Yet another object of the invention is to provide a connector requiring a minimum amount of space in relation to its current carrying ability.
Another object of the invention is to provide a connector of the stab type which is relatively compact requiring a minimum amount of space and which is economical to manufacture.
Still another object of the invention is to provide a stab connector which is comprised of individual parts to facilitate manufacturing and which is quickly and easily assembled without the use of tools into a single operating unit.
DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged fragmentary view of the rear wall of a control unit pan showing the stab connector assembly of the present invention mounted thereon and in engagement with associated buses;
FIG. 2 is a plan view of a stab connector assembly with parts broken away to show internal arrangement;
FIG. 3 is a view in front elevation of the stab connector assembly shown in FIG. 2 with parts broken away to show the internal arrangement;
FIG. 4 is a fragmentary view in horizontal section through a stab connector housing taken in a plane represented by the line IVIV in FIG. 3;
FIG. 5 is a view in vertical section taken in plane represented by the line V-V in FIG. 3;
FIG. 6 is a plan view of a stab connector body shwoing the contacts therein;
FIG. 7 is a view in vertical section through the stab connector body taken in a plane represented by the line vn vn in FIG. 6; and
FIG. 8 is an exploded view of a stab connector showing the relationship of the various parts as they would be assembled.
DESCRIPTION OF THE INVENTION Referring now to FIG. 1 of the drawings, there is illustrated a control center 20 which is constructed and arranged to receive a plurality of control unit pans or drawers, such as the pan 21 depicted. Three bus bars 22A, 22B and 22C are supported in spaced vertical relationship in an insulator support member 23 that is secured to the inner surface of the rear wall 24 of the control center 20. The bus bars extend verticaly and are electrically connected to a horizontal bus bar structure (not shown) in a well known manner.
Three stab connectors 25A, 25B and 25C of the invention are shown carried on a common insulator mounting panel 28 which is secured as by screws 29 to the vertical surface of the rear wall 31 of the pan unit 21. Each of the stab connectors 25A, 25B and 25C are provided, in this instance, with two sets of contacts comprising upper contacts 32A-33A and lower contacts 34A-35A that are associated with the connector 25A. The connector 253 includes an upper set of contacts 328-338 and a lower set of contacts 348-353; and connector 25C is provided with an upper set of contacts 32C-33C and a lower set of contacts 34C-35C.
Copper conducting cables 36A and 37A, 36B and 37B, and 36C and 37C are electrically connected to the inner ends of the contacts 32A-34A and 33A-35A; and, 32B-34B and 33B-35B; and, 32C-34C and 33C-35C, respectively. The cables extend outwardly from the top of the stab connectors and extend through suitable apertures 38A, 38B and 38C provided in the rear wall 31 of the pan 21. The cables are operably connected to control devices (not shown) carried by the pan or drawer 21.
Each of the stab connectors are identical, and therefore, the description of the stab connector 25B will apply to all of the connectors. Control units such as the unit 20 depicted, as well as other types of devices are being made more compact in the interest of conserving space as well as to facilitate the placement and relocation of the units when necessary. As a result of the compactness of such units, components associated with the units of necessity must be made more compact. However, the associated units such as the stab connector 25B cannot, in the interest of compactness, sacrifice strength or performance characteristics, but must maintain their electrical ratings as well as their ruggedness. In maintaining rating characteristics, certain limitations are inherent such as dimensions of the contacts and cables which must be capable of conducting the rated electrical load. Thus, these limitations have heretofore prevented the full realization of compactness with the accompanying requisite of ruggedness and capabilities. One of these limitations is the manufacturing of the compact device such as the stab connector 258 in that the joining of the electrical cable 368 and 378 to the associated contacts 328-348 and 338-358 requires good electrical bonding having good mechanical strength characteristics. Thus, in the past connectors have been relatively large so that adequate access for the necessary tooling required for bonding the cable to the contacts would be provided, or a mechanical fastener was used to connect the cables to the contacts. Also, the assembly of such units was complicated requiring a relatively large number of steps in the assembling process. The stab connector 258 of the present invention provides a rugged, compact, high electrical rated connector which is easily manufactured and which is simple to assemble.
As shown in FIGS. 2, 3, 6 and 7, the stab connector 258 includes a contact body or holder 418 which is of moulded or cast epoxy resin. The holder 418 has a base 428 which is provided with a laterally extending recess 438. The side edges of the base 428 slant inwardly towards the rear edge of the base, as shown in FIGS. 2, 6 and 8. In providing the lateral recess 438, a laterally extending forward base foot 448 and a laterally extending rear base foot 468 are formed.
Upstanding from the base 438 is a forwardly disposed contact support 478 comprising an upstanding front wall 488 and an upstanding rear wall 498. As shown in FIGS. 2, 6 and 8, the rear wall 498 is spaced from and is shorter in width than the front wall 488. An integrally formed cap 508 serves as a reinforcing member to piovide rigidity to the upstanding walls 488 and 498. A horizontal center reinforcing web 518 is also provided between the walls 488-498 and it also serves as a divider to form a pair of horizontal laterally extending compartments 528-538 which are located in the same vertical plane. As best depicted in IFIGSv 1, 2, 6 and 8, the front wall 488 is provided with a pair of top side slots or recesses 548-568 and a pair of side bottom slots or recesses 578-588. The rear wall 498 is likewise provided with a pair of side top slots or recesses 618-628 which are in the same horizontal plane in which the front wall recesses 548-568 are located. A pair of side bottom slots or recesses 638-648 are also formed in the rear wall 498 and are located in the same horizontal plane in which the front wall lower slots 578-588 are located. Thus, the recesses 548-6l8 in effect serve as a single horizontal slot which receives and supports the upper contact 338. In a like manner, the recesses 378-638 and 588-648 operate as slots to receive and support the contacts 348 and 35B, respectively. The recesses formed in the front and rear walls 488 and 49B are constructed in a manner that the associated ones of each of the pairs of contacts, as exemplitied by the pair of upper contacts 328 and 338, are disposed in their associated slots so that their axes intersect at an imaginery point rearwardly of the holder 418. The upper and lower recesses are formed in identical manner so that the contacts of the upper and lower sets of contacts are in the same vertical planes.
For maintaining the pair of contacts 328-338 the pair of contacts 348-358 in cooperative operating position within their respective slots or recesses in the holder 418, resilient biasing means such as tension springs 668 and 678 are provided. The tension spring 668 is disposed in the bore 528 and is adapted to have its opposite ends connected to the contacts 328-338.
In a similar manner the tension spring 678 is disposed within the bore 538 and is adapted to have its opposite ends connected to each of the lower contacts 348-358. Thus the uppermost pair of contacts 328-338 is resiliently retained in operative position within their associated upper slot or recesses by operation of the spring 668. Likewise, the lowermost pair of contacts 348-358 is resiliently retained in operative position within their associated lower recesses by operation of the spring 678.
A casing or housing 708 for receiving and retaining the contact holder 418 with contacts therein in a compact protected assembled unit is provided. As shown, the casing 788 is integrally formed as a part of the mounting panel 28. Howver, it will be appreciated that the casing 708 could readily be an individual component suitable for independent mounting, as desired. The casing 708 includes a base 718 which serves as a supporting slide surface on which the holder 418 slides as it is inserted into the casing. Upstanding from the base 718 in spaced relationship are side walls 728 and 738 which at their upper edges are provided with integral inwardly projecting flanges 74B and 768 which operate to retain the holder 418 in the casing 788. The mounting panel 28 serves as the rear wall 778 of the casing. Formed in the inner surface of the rear wall 778 in vertical spaced relationship are a pair of recesses 788 and 798 which form a centrally located projection 818 that is disposed equi-distant from the side walls 728 and 738. The elongated recesses 788 and 79B receive the rearwardly extending ends 838 and 84B of the upper pair of contacts 328-338 and 348-358 are so disposed in the contact supporting portion 478 of the holder 418 that the rearwardly extending ends of 838-848 and 868-878, respectively, extending rearwardly beyond the rear edge of the base 428. Thus, upon insertion of the contact holder 418 into operative position within the casing 708, the rearwardly extending ends 838-848 and 868-878 of the two pairs of contacts will abut the projection 818 so that the holder 418 cannot be fully inserted into the casing. It is therefore necessary to force the rearwardly extending ends 838-84 and 868-878 of the pairs of contacts 328-338 and 348-358, respectively, laterally away from each other so that they enter into the recesses 78B and 798 to permit full insertion of the holder 418 into the casing 708. The spreading of rear ends 838-848 and 868-878 of the contacts 328-338 and 348-358 is easily accomplished by applying an inwardly acting force simultaneously to the forward bus bar engaging ends of the pairs of contacts. An inwardly acting force applied to the outer ends of the contacts will cause the contacts to pivot on the vertical inner surfaces of the associated ones of the recesses 51B, 528, 548, 568,578 and 588. With the holder 418 fully inserted into an operative position within the casing 708, the force applied to the outer ends of the pairs of contacts 328-338 and 34B-358'is released and the inner ends 838-848 and 868-378 of the contacts, by operating springs 668-678, forcefully engage against the respective sides of the projection 818, as depicted in FIG. 2.
To lock the contact holder 418 in operative position within the casing 708, a resilient locking arrangement is provided. To this end the upper surface of the casing base 718 is provided with a recess 918 which is adapted to receive a resilient member 928, as shown in FIGS. 3, 5 and 8. The resilient member in the preferred embodiment is an arcuate leaf spring with the edges 938 and 948 rolled slightly backward towards the crown portion of the spring.
In operation the spring 928 is placed in the casing base recess 91B in a manner that the convex or crown portion of the spring rests in the recess 91B recess. In this manner the lateral edges 938 and 948 are parallel to sides 728-738 of the casing and are disposed above the base surface but not in contact therewith. With this condition obtained, the lateral edges 938 and 948 of the spring are free to flex downwardly. Thus, as the contact holder 418 is inserted into the casing 70B, the depending rear foot or edge 46B of the holder will force the lateral edges 938-948 of the spring 918 downwardly as the housing is inserted inwardly into the casing 708. With the holder 418 fully inserted into the casing 708, the depending rear edge 468 will pass off of the lateral edges 938-948 of the spring 918 thereby releasing them. The lateral edges 938-948 upon being released flex upwardly engaging behind the vertical inner surfaces of the front and rear feet or edges 448 and 468, locking the contact holder 418 in operative position within the casing 70B. The spring 928 in its locking operation exerts an upwardly acting force on the contact holder 418. This upwardly acting force serves to engage the upper surface of the contact support portion 418 of the holder with the under surfaces of the inwardly extending flanges 74B and 768. As a result, the holder 41B and casing 70B become a single operative stab connector unit.
As previously mentioned, the inner ends 838-848 and 868-878 of the contacts 328-338 and 348-358 are forced apart so as to engage the vertical edges of the projection 818. Under this condition the outer or forwardly projecting ends of the contacts 328-338 and 348-358 are maintained in dimensional spaced relationship by the inner surfaces of the recesses 54B, 56B, 57B and 588 of the front wall 488 of the support portion 478. This relationship is depicted in FIG. 2 wherein the upper pair of contacts 328-338 are shown in operative position in the holder 418 which is in the casing 708. As there shown, the inner ends 838-848 of the contacts 328-338 are disposed in abutting relationship on each side of the projection 818. As a result, in this position contacts 328-338 do not abut the vertical edge surfaces of the recesses 618-628 of the rear wall 498, but do engage the vertical inner surfaces of the recess 568 of the front wall 488 of the support portion 478. As similar conditions are obtained for the contacts 338, 348-358, as depicted in FIG. 2, it is apparent, therefore, that the contacts 328-338 and 348-358 are forcefully urged toward each other by operation of their associated springs 668-678. It is also apparent that the spacing between the outer ends of the contacts 328-338 and 348-358 is determined by the depth of the recesses 548-568 and 578-588. In practice, the construction of the recesses 548-568 and 578-588 is such that with the contacts 328-338 and 348-358 in operative position, the distance between the contacts of each of the pairs of contacts will be slightly less than the minimum diameter of the bus bar 228 that the stab connector will be associated with.
From the foregoing description it will be apparent that the engagement of the stab connector 258 with the bus bar 228 will force the pairs of contacts 328-338 and 348-358 outwardly away from each other. With the springs 668-678 operating to apply an oppositely acting force on the contacts, the contacts will pivot on the sides of the projection 818. Thus, the contacts 328-338 and 348-358 when engaged with the bus bar 228 will not be in contact with the sides of the recesses 618-628 and 638-648 in the rear wall 498, but a space, as depicted in FIG. 2 and exemplified by the contacts 348-358, will exist therebetween. As a result, the contacts 328-338 and 348-358 will engage with the bus bar 228 with equal pressure, even though the contacts are misaligned with respect to the axis of the bus bar. This is true because of the equalized force that the springs 668 and 678 apply to their respective contacts. Not only is the advantage of equal contact pressure obtained, but also the area of contact between the contacts and the bus bar remains constant even though the mating contacts are misaligned.
Prior to assembling the contacts in the contact holder 418, the conductor cable 368 and 37B is electrically connected to the inner ends of the contacts. Thus, as depicted in FIGS. 2, 3, 6, 7 and 8, the conductor cable 368 is electrically connected to the inner ends of the two left contacts 328-348 and the cable 378 is electrically connected to the inner ends of the contacts 338-358. Since the contacts prior to being assembled into the holder 418 are individual loose pieces, the connection of the cable 368 to the contacts may be easily accomplished as by resistance welding. Resistance welding of the cable to the contacts results in a highly efficient, low resistant and economical connection with a minimum space required. This has not heretofore been possible with presently known connections. This is true because the presently known connectors are moulded into a casing prior to the cables being connected thereto. As a result, space and the moulded case itself prevents the use of resistance welding equipment and the advantages of resistance welding are not obtainable. The cable 378 is similarly connected to the right contacts of contacts 338-358. Since the connection of the cables 36B and 37B is made to contacts prior to assembly, the most economically suitable manufacturing conditions can be utilized to effectively reduce the manufacturing costs of the stab connectors. It will also be appreciated that inspection of the resistance weld may be accomplished prior to assembly to insure that all strands of the flexible cable are fusedand free of pits, voids and strand separation. This reduces the possibility of arcing between the strands of the cable and also between the two cables 368 and 378. As a result, improved performance is obtained and electrical erosion reduced to a minimum.
As shown in FIGS. 1, 2 and 7, the contact holder 418, as previously mentioned, includes the contact support portion 478. This contact supporting portion 478 is formed so that its rear face 998 is in a plane that intersectsthe base 428 approximately midway between the front and rear edges of the base. Thus, a sufficient and convenient space exists between the rear wall 498 of the support portion 478 and the rear surface of the casing, as shown in FIG. 2. This space has been provided to facilitate assembly of the stab connector and the insertion of the free ends of the cables 36B and 378 through the associated openings 388 in the rear surface of the pan 21. The pairs of contacts 328-338 and 348-358 with their associated cables 36B and 378 connected thereto are assembled into the holder 418. The free ends of the cables 368 and 37B are then inserted through the associated one of the openings 388 and the holder 41B is inserted into position in the casing 705, As the holder is inserted into the casing 708, the cables are also drawn further through the openings 388. This simultaneous feeding of the cables through the openings 33B and the insertions of the holder 3113 into the casing 708 in conjunction with the space provided between the holder 41B and the casing 708 ensures that the bends in the cables 36B and 3713 will have a smooth radius of curvature and that highly undesirable sharp corners are avoided.
From the foregoing detailed description of the invention it is apparent that there has been disclosed new and improved stab connectors having all the advantages of the moulded case type without the manufacturing disadvantages and having all the advantages of individual components without the disadvantages thereof, The disclosed stab connector not only substantially reduces manufacturing cost, but combines the advantages of economy with ruggedness without sacrificing compactness.
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. ln an electrical connector for connecting a plurality of cables to a bus;
a pair of individual contacts to which said cables are attached;
a holder provided with a base plate;
an upstanding abutment on said base plate having a front face surface coinciding with the front edge surface of said plate, said abutment extending rearwardly from the front edge of said base plate for a distance less than the depth dimension of said base plate, with the sides of said abutment coinciding angularly with the side edges of said base plate;
a slot formed in each side of said abutment and adapted to receive said contacts, said slots having axes which converge rearwardly of the front face of said abutment;
resilient means carried by said abutment and connected to said contacts, said resilient means being operable to resist the displacement of said contacts away from each other when said contacts are engaged with a bus; and,
a casing adapted to receive said holder with said contacts as a unit.
2. An electrical connector according to claim 1 wherein said abutment and said side edges of said base plate cooperate to form the opening through which said cables extend to the exterior of said casing 3. An electrical connector according to claim 1 wherein said casing includes a base, a pair of spaced apart side walls and a rear wall;
inwardly extending flanges formed integrally with each of said side walls of said casing, said flanges operating to contain said holder within said casing, said flanges in cooperation with the rear wall of said casing and the rear surface of said abutment defining an opening to permit unrestricted passage of the cables to the interior of said casing;
an abutment formed on the interior surface of the rear wall of said casing;
said slots being formed in said abutment in a manner that the axes thereof intersect at a point rearwardly of said abutment; and, said contacts are disposed within said slots in a mannet to have the inwardly disposed ends thereof engaging on each side of said casing rear wall abutment to effect a spreading of the inner ends of said contacts against the contracting effort of said tension spring and said outer ends of said contacts being displaceably away from each other when in engagement with a bus and said tension spring thereby urging the outer ends of said contacts towards each other into good electrical contact with said bus. 4. An electrical connector according to claim I wherein said abutment is provided with a pair of vertically spaced horizontally extending grooves of each side thereof; said contacts are disposed within said abutment slots in a manner that the inner ends of said contacts extend rearwardly beyond said abutment and the forward end of said contacts project outwardly from the front face of said abutment for engagement with a bus bar; and,
said resilient means comprising a tension spring is carried by said abutment and connected to both of said contacts, said tension spring operating to forcefully maintain said contacts in said slots with their axes parallel to the axis of said slots,
whereby the bracketing engagement of the forwardly projecting ends of said contacts with a bus bar which tends to force the outwardly extending contact ends away from each other is resisted by said tension spring and said contacts engage said bus with equal pressure.
5. An electrical connector according to claim 4 wherein said contacts are loosely disposed within said slots and said tension spring also operates to maintain the contacts in operative position within said slots.
6. An electrical connector according to claim 1 wherein there is provided a resilient member disposed between said holder and said casing and operable to releasably lock said holder in position in said casing.
'7. An electrical connector according to claim 6 wherein the surface of said holder base adjacent to the bottom of said casing is provided with a recess;
the surface of the bottom of said casing adjacent to holder base is provided with a recess; and,
said resilient member is disposed within said recesses in a manner to effect an interlock between said holder and said casing.
3. in an electrical connector for a plurality of cables:
a pair of contacts carried by said holder in spaced relationship;
means operable to resiliently secure said contacts in operative position in said holder said means being operable to permit said contacts to be displaced away from each other; and,
a casing adapted to receive said holder with said contacts as a unit.
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|U.S. Classification||439/251, 439/701|
|International Classification||H02G5/00, H02G5/08|